Reinsurance (Reinsurance Transactions Effect) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Effect of reinsurance transactions on our premium, loss and loss adjustment expense and policy acquisition costs
Direct written premium	$ 717,048us-gaap_DirectPremiumsWritten	$ 620,512us-gaap_DirectPremiumsWritten
Reinsurance assumed	109,088us-gaap_AssumedPremiumsWritten	126,210us-gaap_AssumedPremiumsWritten
Reinsurance ceded	(157,220)us-gaap_CededPremiumsWritten	(156,540)us-gaap_CededPremiumsWritten
Net written premium	668,916us-gaap_PremiumsWrittenNet	590,182us-gaap_PremiumsWrittenNet
Direct earned premium	703,584us-gaap_DirectPremiumsEarned	637,313us-gaap_DirectPremiumsEarned
Reinsurance assumed	71,168us-gaap_AssumedPremiumsEarned	76,023us-gaap_AssumedPremiumsEarned
Reinsurance ceded	(174,189)us-gaap_CededPremiumsEarned	(150,724)us-gaap_CededPremiumsEarned
Net earned premium	600,563us-gaap_PremiumsEarnedNet	562,612us-gaap_PremiumsEarnedNet
Direct loss and loss adjustment expense	458,726	359,629
Reinsurance assumed	27,216	41,802
Reinsurance ceded	(120,780)	(70,685)
Net loss and loss adjustment expense	365,162	330,746
Policy acquisition costs	115,070hcc_PolicyAcquisitionCosts	104,645hcc_PolicyAcquisitionCosts
Ceding commissions	(39,859)hcc_CedingCommissions	(35,604)hcc_CedingCommissions
Net policy acquisition costs	$ 75,211	$ 69,041

Ceding commissions.

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Policy acquisition costs.

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Amount of earned premiums assumed from other entities.

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Amount, before premiums ceded to other entities and premiums assumed by the entity, of premiums earned.

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Amount, before effect of policies assumed or ceded, of expense related to provision for policy benefits and costs incurred.

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Amount of policy benefits and costs incurred for policies assumed.

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